isdparser: Parse 'NOAA' Integrated Surface Data Files

Tools for parsing 'NOAA' Integrated Surface Data ('ISD') files,
described at <https://www.ncdc.noaa.gov/isd>. Data includes for example,
wind speed and direction, temperature, cloud data, sea level pressure,
and more. Includes data from approximately 35,000 stations worldwide,
though best coverage is in North America/Europe/Australia. Data is stored
as variable length ASCII character strings, with most fields optional.
Included are tools for parsing entire files, or individual lines of data.